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Systematics And Reproductive Ecology Of The Germplasm Resources Of Oenanthe

Posted on:2016-05-12Degree:DoctorType:Dissertation
Country:ChinaCandidate:S FuFull Text:PDF
GTID:1310330482959181Subject:Botany
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The Oenanthe L. belongs to the family Apiaceae and subfamily Apiodeae. Some of the species in this genus have been used as a vegetable and as a traditional medicine for a long time in East Asia. However, due to the morphological variability of the plants, the genus has been regarded as a taxonomically complex genus. In order to clarify the taxonomic status of Oenanthe accessions and provide baseline data for future sustainable use of the genetic resources, in this study, we first studied the systematics of the genus by using the nuclear ITS region DNA sequences; we then used optical microscope and electron scanning microscope to study the the leaf epidermis morphology and pollen morphology of representive germplasm resources of Oenanthe; in addition, we also studied the reproductive ecology of several germplasm resources through field observations. The main results of these study are listed here below:(1)we examined the sequence variation of the ITS region of Oenanthe accessionscollected from a wide geographic range in China and other countries (Japan, Sourth Korea) in the present study. For a comparison, the ITS sequences available in GenBank in Oenanthe were also included in our analyses. Both phylogenetic tree construction methods (BI and ML) revealed that accessions collected in this study tended to cluster into two groups, which were shown to be close related to the species O. mildbraedii and O. sarmentosa, separately. However, these two species have never been recorded in both China and the neighbor countries. Therefore, it seems probablely that, the Oenanthe accessions have been given names in our sampled localities, such as, O. javanica etc. Future works, including carefully checking the morphological characters and ITS sequence region of more accessions of each species in Oenanthe worldwide, are still needed to clarify the taxonomic status of the genus.(2)We used optical microscope and electron scanning microscope to observe the the leaf epidermis morphology of 15 resources from 3 species of Oenanthe (O. javanica (B1.) DC; O. sinensis Dunn and O. dielsii de Boiss), which sampled from Wuhan aquatic vegetable garden. The results are as follows:(a) The microscope shows stomatal apparatus normally excited in the upper and lower epidermis of the leaves. A few resources have little stomatal apparatus, the shapes of the stomatal apparatus are ruleless. Most of the leaf epidermal cells are polygonous with no rules. We can seperate the anticlinal wall from its styles, such as almost straight, straight, flat bow, light wave and wave; (b) scanning electron microscopy (SEM) observation shows that arch cover of leaf epidermis stomatal apparatus is smooth with the shape of light wave or wave. Cutin membrane is stripy. Some of the stripes are ridge, some have particles and cluster on it; (c) The distribution of stomatal apparatus. The shape of stomatal apparatus's ongoing cover and cutin membrane etc. can provide some reference value to distinguishing among some species in the genus.(3)We used optical microscope and electron scanning microscope to observe the pollen morphology of 14 resources from 3 species of Oenanthe (O. javanica; O. sinensis and O. dielsii. The results showed that the morphological features are 5 different kinds, Oval, round, rectangular, a few are long oval (He qing Water dropwort) and near diamond (Yangzhou Water dropwort). The length of the polar axis(P) is from 20.6 to 28.5?m, most of them are between 21 and 26?m.The length of the equatorial axis is from 12.7to 17.9?m, most are between 14 and 16?m. PE is from 1.2 to 1.9?m, most of them were 1.2-1.6?m. The shape of the polar view is normally blunt triangle. Some are near circular, three crack circular or four crack circular. Only the Heqing Water dropwort is near the square. The germ pore is a three furrows pore, most of them are edge germ pores. The germ pore furrows are as long as the poles. The ornamentations in the the equator zone are dense and diverse. They can be seperated into 3 different ornamentations on the whole:short wrinkle net ornamentation, granular ornamentation and net ornamentation. According to the results of observation, we discussed 3 different species of water dropwort's evolutionary status and Species'relationship within genus. Then combined with the observation of the morphological characteristics we discussed the classification problem of the Oenanthe L.(4)In our field observations, we recorded the blooming dynamic, forms of floral organ, pollination characteristics and breeding system. The results are as follows:(a) the flowering phase lasts for alomst 4-5 days. Umbrella inflorescence's flowering phase lasts for 10 to 12 days. Single flower lasts for 4 to 6 days. Pollen began to scatter on the first day of flowering. The anthers are above the stigmas. Two sigmas obviously extend and unfold after the falling of petals and stamens, (b) the activity of Water dropwort's pollen grain is short. The activity of the pollen grain is as high as 96.31% in the beginning of flowering. It obvious decreaced after 3 hours later. The activity is almost gone after 24 hours. (c) Female flowers stigma can be pollinated in 4 or 5 days very nicely. It weakens after 6 days. For 7 days after, it basically can't be pollinated at all. (d) based on the OCI, P/O and fructification percentage after castration and bagging, it showed that the water dropwort's breeding system is outcrossing, some of them are selfing affinity and need pollinators.
Keywords/Search Tags:Apiaceae taxonomy, Breeding system, ITS, leaf epidermis, Oenanthe, Pollination Biology, systematic research, Water dropwort
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